The invention relates to an electrodeless low-pressure discharge lamp comprising a lamp vessel which is sealed in a vacuum-tight manner and is filled wtih a metal vapor and a rare gas, and a core of magnetic material surrounded by a winding connected to a high-frequency supply unit which, during operation of the lamp produce an electric field in the lamp vessel, the inner side of the lamp vessel being provided with a transparent conductive layer.
Such a lamp is known from Netherlands patent application No. 8205025 laid open to public inspection and corresponding U.S. Pat. No. 4,568,859.
In the known lamp, the transparent conductive layer on the inner side of the lamp vessel is connected during operation of the lamp to one of the lead-in wires of the supply mains. In this way the electric field originating from the lamp is substantially confined to the lamp vessel and its strength outside the lamp is sufficiently small that the production of high-frequency interference currents in the supply mains is prevented. The conductive layer is connected by means of a lead-through member for interference currents to an electrical conductor located outside the lamp vessel. The current lead-through member is secured in the known lamp at the area of the connection of a sealing member of the lamp vessel. Use is then made of connection material consisting of glass enamel in order to obtain a reliable gas-tight connection. This use of a separate lead-through member is unfavorable. Moreover, during the manufacturing process, oxidation of the metal of the lead-through conductor is liable to occur, which adversely affects the conducting properties. Moreover, the use of glass enamel involves a time-consuming and complicated procedure.